EnergyPlus - Surface Outside Face Sunlit Fraction for Shading Devices
I am using EnergyPlus in order to calculate the sunlit fraction (by unreflected beam solar radiation, as specified in the Input-Output Reference) of window glazing areas with the presence of external shading devices (e.g. venetian blinds, shades). The output values of Surface Outside Face Sunlit Fraction seem to be unaffected by the presence of these shading devices.
I also tried another case: I removed the shading devices and added an overhang (through the Shading:Building:Detailed object in EnergyPlus). This time I get variable output values of Surface Outside Face Sunlit Fraction, indicating that the overhang was taken into account.
So, is it safe to suppose that, at the moment (at least), EnergyPlus cannot calculate the sunlit area of external surfaces that are shaded by shading devices like blinds, shades, screens etc.(I guess it has to do with the polygon clipping algorithms) ?
Or is there a way that can be calculated in EnergyPlus?
Just to provide a little more detail are you using WindowProperty:ShadingControl with WindowMaterial:Shade and WindowMaterial:Blind, or you drawing Shading:Building:Detailed similar to your overhang example? If you are not suing shading surfaces then I think your assumption is correct that it won't affect sunlit fraction of window surface, but I don't know that it has anything to do with polygon clipping.
Hi David! I am defining my shading devices (blinds, shades) using WindowProperty:ShadingControl with WindowMaterial:Shade and WindowMaterial:Blind.